Elevated shower activity during the early morning hours of Wednesday, May 20th, enabled strong mid level winds, associated with a nocturnal low level jet, to mix down to the surface in the form of a downburst. Winds up to 65 mph were estimated from the Bismarck Doppler radar, and resulted in some structural damage to a farmstead just south of St.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BIS wrote it up.
Elevated shower activity during the early morning hours of Wednesday, May 20th, enabled strong mid level winds, associated with a nocturnal low level jet, to mix down to the surface in the form of a downburst. Winds up to 65 mph were estimated from the Bismarck Doppler radar, and resulted in some structural damage to a farmstead just south of St. Anthony in Morton County. In addition, compressional heating of the descending air resulted in temperatures of 90.5 and 94.6 recorded on two different thermometers seven miles south of St. Anthony.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Bismarck, ND wrote its last area forecast discussion before the first event at May 19, 2:40 PM CST, 10 hours 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 340 PM CDT TUE MAY 19 2009 .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT... MAIN FORECAST PROBLEM IN THE SHORT TERM WILL BE SLIGHT CHANCES OF PRECIPITATION. OVERALL CHANCES APPEAR SMALL AND BIGGEST PROBLEMS WILL BE PARING DOWN AREAL EXTENT OF HIGHER POPS WITHOUT GOING TOO FAR. WILL UTILIZE A GFS/NAM BLEND WITH A NOD TO THE GFS FOR SPECIFICS. CURRENTLY...STRONG SOUTHEAST SURFACE FLOW ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AS SURFACE LOW DEVELOPS OVER THE LEE OF THE MONTANA ROCKIES. ATMOSPHERE IS STILL PRETTY STABLE OVER THE AREA WITH MEAGER LOW LEVEL MOISTURE...ESPECIALLY NORTH. WE DO SEE SOME MID 50S DEWPOINTS PUSHING INTO NORTH CENTRAL AND NORTHEAST SOUTH DAKOTA. MOISTURE TRANSPORT WILL CONTINUE INTO THE AREA TONIGHT. SURFACE GRADIENT WILL WEAKEN AS WE DE-COUPLE THIS EVENING...BUT STRONG LOW LEVEL JET LIFTS INTO THE SOUTH CENTRAL AND EAST...ALONG WITH THE SURFACE WARM FRONT. WARM TEMPERATURES ALOFT WILL INHIBIT CONVECTION HERE AND WILL NOT RAISE POPS ENOUGH TO BRING A MENTION OF THUNDER...BUT THERE IS AT LEAST A SMALL RISK OF AN ISOLATED THUNDERSTORM HERE. FARTHER WEST...THE MOST LIKELY AREA FOR CONVECTION WILL BE THE NORTHWEST LATE THIS EVENING...SPREADING ACROSS THE NORTHERN TIER COUNTIES OVERNIGHT. THIS IS ASSOCIATED WITH COOLER UPPER TEMPERATURES MOVING INTO THE AREA BEHIND LOW PRESSURE SYSTEM AND COLD FRONT. ON WEDNESDAY...THE COLD FRONT EXITS THE SOUTHEAST CWA BY MIDDAY. THERE MAY STILL BE ENOUGH MOISTURE AROUND IN THE SOUTHEAST FOR A THUNDERSTORM OR TWO...BUT THE BEST MOISTURE AVAILABILITY AND INSTABILITY WILL RESIDE TO THE SOUTH AND EAST OF THE LOCAL AREA. WE COULD ALSO SEE AN ISOLATED SHOWER OR TWO ACROSS THE NORTH IN THE AFTERNOON DUE TO THE COLD TEMPERATURES ALOFT. HOWEVER...WITH SUCH A DRY ATMOSPHERE AND WITH SUBSIDENCE BEHIND THE FRONT...EXPECT MOST IF NOT ALL OF THE AREA WILL SEE LITTLE IF ANY PRECIPITATION. GRADIENT WINDS TODAY DO NOT APPEAR AS STRONG AS THEY DID YESTERDAY...BUT WE SHOULD STILL BE BREEZY TO WINDY IN THE AFTERNOON AS WE MIX OUT. HAVE KEPT THE REMAINDER OF THE SHORT TERM FORECAST DRY. A COUPLE OF PROBLEMS TO KEEP AN EYE ON. FIRST IS A POSSIBLE FROST ADVISORY THURSDAY MORNING. CURRENTLY WE ARE FORECASTING MID 30S FOR A GOOD PORTION OF THE WEST. IF THIS HOLDS...WE MAY NEED TO CONSIDER A FROST ADVISORY TOMORROW. CERTAINLY DOESNT LOOK COLD ENOUGH AT THIS TIME TO WARRANT A FREEZE WATCH. MODELS ARE ALSO DEPICTING SOME LIGHT QPF ON FRIDAY DUE TO A WEAK SHORTWAVE TROUGH MOVING THROUGH A ZONAL TO NORTHWEST FLOW. WILL CONTINUE TO MONITOR BUT NOT A STRONG ENOUGH SIGNAL AT THIS TIME TO INTRODUCE POPS. .LONG TERM...SATURDAY THROUGH TUESDAY BIG DIVERGENCE IN THE GFS/ECMWF BEYOND SATURDAY. THE 12Z GFS KEEPS MAINLY A ZONAL FLOW WAFFLING TO A NORTHWESTERLY FLOW ALOFT AT TIMES. THE 12Z ECMWF TURNS THE FLOW SOUTHWEST SATURDAY AND BRINGS AN IMPRESSIVE WAVE AND PRECIPITATION THREAT SATURDAY NIGHT THROUGH MONDAY OVER CENTRAL AND EASTERN NORTH DAKOTA. THE GEMGLB RESEMBLES THE GFS RATHER THAN THE ECMWF. FOR NOW WILL KEEP A SLIGHT CHANCE OF SHOWERS/TSTMS SUNDAY INTO MEMORIAL DAY AND WAIT FOR BETTER CONSENSUS BEFORE SHIFTING TO THE ECMWF SOLUTION. SEASONAL TEMPERATURES THROUGH THE PERIOD. && .AVIATION...LOW PRESSURE AND ASSOCIATED WARM FRONT WILL MOVE THROUGH THIS EVENING...FOLLOWED BY A COLD FRONT TONIGHT. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE WITH THE PASSAGE OF BOTH WEATHER FRONTS BUT THE BEST OF PRECIPITATION WILL OCCUR WITH THE PASSAGE OF THE COLD FRONT. SOUTHEAST WINDS THIS AFTERNOON AND TONIGHT OF 15 TO 30 MPH WILL VEER TO THE WEST AND NORTHWEST TONIGHT INTO WEDNESDAY. EXPECT NORTHWEST WINDS OF 15 TO 25 MPH WEDNESDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && TWH/KS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BISMARCK ND 448 AM CDT TUE MAY 19 2009 NDZ001-002-009-010-017>023-031>034-040>044-201000- DIVIDE-BURKE-WILLIAMS-MOUNTRAIL-MCKENZIE-DUNN-MERCER-OLIVER- MCLEAN-SHERIDAN-WELLS-GOLDEN VALLEY-BILLINGS-STARK-MORTON-SLOPE- HETTINGER-GRANT-BOWMAN-ADAMS- 448 AM CDT TUE MAY 19 2009 /348 AM MDT TUE MAY 19 2009/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST NORTH DAKOTA...SOUTH CENTRAL NORTH DAKOTA AND SOUTHWEST NORTH DAKOTA. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND THUNDERSHOWERS THIS MORNING...AND A CHANCE OF THUNDERSTORMS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY...AND AGAIN ON SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. NDZ003>005-011>013-201000- RENVILLE-BOTTINEAU-ROLETTE-WARD-MCHENRY-PIERCE- 448 AM CDT TUE MAY 19 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL NORTH DAKOTA. .DAY ONE...TODAY AND TONIGHT A FREEZE WARNING IN EFFECT THIS MORNING. ALSO SCATTERED SHOWERS AND THUNDERSHOWERS THIS MORNING...AND A CHANCE OF THUNDERSTORMS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY...AND AGAIN ON SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. NDZ025-035>037-045>048-050-051-201000- FOSTER-BURLEIGH-KIDDER-STUTSMAN-SIOUX-EMMONS-LOGAN-LA MOURE- MCINTOSH-DICKEY- 448 AM CDT TUE MAY 19 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL NORTH DAKOTA AND SOUTHEAST NORTH DAKOTA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY...AND AGAIN ON SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. JV
1 high wind. Local standard time, as filed.
Strong downburst winds caused eight foot corral walls to be thrown 25 feet from their original location on a farmstead south of St. Anthony.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Dakota in 2009Every state in 2009This day in weather historyWarnings in North Dakota, May 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 163917.